I'm building an autonomous boat (1m length), which is supposed to sail at a fixed speed over ground of 1m/s. Currently I set the cruise throttle (PWM signal) such that in no-current conditions the speed is around 1m/s. However, when the boat is facing wind, waves or current, the speed drops. Since i entered '1' in cruise_speed, I was expecting that the autopilot would increase throttle in order to match the speed to 1m/s. It doesn't however. The maximum speed of the boat is 3m/s, so there is plenty margin for the boat to increase throttle. Any ideas how to make sure the boat makes sure the speed over ground (measured by 3DR GPS) matches the desired speed also when facing tidal currents?